Centerless grinder



sep-1. 14,1926.

w. J. PEE'rs canTEaLss emanan Filed June 14, 1921 4 Sheets-Sheet 1 4 Il INVNTQR Sept` 14, 1926.

- W. J. PEETS cEN'rERLEsS GRINDER Sheets-Sheet 2 l Filed-June 14 1921 INVENTOR WIT W. J. PEETS cENTERLEss GRINDER V Sept. 14 1926.

I 4 Sheets-Sheet 4.

Fiied June 14', 1921 ITTORNEY Patented Sept, 14, 1926.

UNITED STATES PATENT OFFICE. l

WILEUE J. PEE'rs, 0E ELIZABETH, NEW JEEsEY, AssIGNoE fro.y THE SINGER MANU- FACTURING COMPANY, OFVELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY.

Application filed June 14, 1921. Serial No. 477,355;v

This invention relates to an automatic centerless grinder and has for an object to provide a grinder of the centerless type in which the articles to be ground are automatically fed to the grinding point from a source of supply and' also automatically discharged from the grinding point after the grinding operation has been completed. It is also-an object of the invention to provide a machine of this type which will simultaneously grind two or more s'paced bearings on a single article such as a crank-shaft.

With these and other objects in view, the machine, in its preferred form, is provided with one or more sets of peripherally opposed grinding and work-rotating and governingv or controlling wheels. The grinding wheel or wheels is or are mounted on a slide which in operation may be continuously reciprocated in a direction longitudinally of the axes of the wheels which are rotated at a relatively high speed.

The work rotating or governing wheel or wheels is or are mounted on a separate slide which Vis automatically fed toward and from the periphery of the grinding wheel to allow for the insertion and removal of the work and also .operates a work-feeding means in proper timing relation therewith.

Referring to the accompanying drawings, Fig. lis a front elevation of my grinder. Fig. 2 is a transverse section substantially on the line 2-.-2 of Figs. 1 and 4.` Fig. 3 isa transverse section substantially on the line 3-3 of Figs. 1 and 4. Fig. 4 is a top plan view upon a reduced scale. Fig. 5 is a detail plan view of the cam-'plate for shifting the governing wheel. Fig. view of a work-support. Fig. 7 is a side elevation thereof. Fig. 8 is a detail of the means for reciprocating the grinding wheel. Fig. 9 is a viewshowing the development of the camgroove -in the cam-cylinder 92, and Fig. l0 is a detail view of a portion of the work feeding mechanism on an enlarged scale.

In `its preferred form my invention com- E `prises a frame 1 provided on its top surface with a slideway comprising an inverted V 2 and a plain bearing rib 3 upon which is mounted a slide 4 which carries one or more grinding wheels 5. In the present instance -two grinding wheels are shown. VThese grinding wheels are what are termed pecEN'rEaLEss GRINDEE.

6 is a detail end ripheral grinders in that the grinding surface is on the periphery of these wheels. Each wheel is supported by a shaft 5 which is mounted to rotate in spaced bearings 6 and 7 mounted upon the slide 4.- Tlie grindverjshaft between the bearings is provided with a pulley 8 which is driven by means of a belt 9 passing to a driving pulley 10 mounted upon the main power-shaft 11 which rotates in bearings 12 and 13 in the frame 1. The shaft l1 is located below the slide upon which the grinding wheels are mounted so that it and the driving pulleys are located within `the frame and are com-i pletely enclosed thereby. A

Fulcrumed upon the shaft 11 is a frame 14 having a free arm at the end of which is rotatably mounted an idler-pulley15 adapted to bear against the belt 9 and this frame 14 also has an arm 16 to which is attached one end of-a spring 17, the other end of this spring being secured to an eye bolt or equivalent device 18 mounted in the frame 1. The spring 17 tends to turn the fra-me 14 on the shaft 11 and through the idler pulley 15 maintains the belt 9 tight at all times. It will be noted from Fig. 3 that the belt 9 passes upwardly from the pulley 10 through a convenient opening 19 formed in the upper wall of the frame 1.

The slideway "2-3 extends longitudinally of the frame 1 and substantially parallel withthe axes of the grinding wheels, the slide 4 being formed with inverted V and plain surfaces to slide upon the surfaces 2 and 3. The slide 4 is also formed on its upper surfaces with slideways 20 extending transversely of the sli'deway 2 3, and mounted to slide in each of the slideways is a second slide 22 whichcarries the bearings 6 and 7 for the grinding wheel shaft 5 there being a slide for each wheel. The outer end of this slide is provided with a bearing 23 in which is mounted a rotatable. screw 24 having screw-threaded engagement with a lug 25 on the slide 4 and is provided at its v outer end with a gear 26. A second gear 27 .mounted thereon adjacent thebearing 30 a REISSUED the slide 4las desired. The shaft'33 carrying the worm 32 and the disk 34 -is mounted in an adjustable bearing 36, this bearing being fulcrumed on a portion 37 of the frame `integral with the bearing 30 and is provided with acurved slot 38 through which a bolt 39 screwed into the support 37 extends. By loosening the bolt 39 the bearing 36 may be turned about its fulcrum 36 to move the worm 32 out of mesh with the Worm-Wheel 3l and a crank may then be applied to the square end 40 of the shaft 28 allowing rapid rotation of the screw 24 to give a rapid rough adjustment to the slide 22 supporting the grinding wheel.

The grinding wheels are mounted upon the slide 4 so that they may be reciprocated continuously longitudinally of their axes during the normal grinding operation. The amount of this reciprocation is small, in the present instance, about three-sixteenths of an inch being sufficient. The amount of reciprocation, however, depends upon the type of work to be performed. In some classes of workno reciprocation is given to the grinding wheels. The reciprocatory movement is imparted to the slide 4 by means of a crank which is rotated from the main power-shaft 11. As shown more clearly in Fig. 2 a short shaft 41 is mounted in the frame 1 above the main power-shaft 11 and these two shafts are provided with intermeshing spur-gears 42 and 43 respectively. The shaft 41 is also provided with a worm 44 meshing with a Worm-wheel 45 on a vertical shaft 46, which latter shaft at its upper end carries a collar 47 having a transverse groove 48 in which is adjustably mounted a block 49 (Fig. 8). The collar 47 is provided with adjusting screws 50 and 51 extending through the walls thereof from opposite ends of the groove 48 and bear upon the ends of the block 49. By adjusting these screws the block 49 which carries a pin 52 may be adjusted to locate said pin eccentrically of the shaft -46 and the amount of this eccentricity will determine the amount of throw of the pin 52 as the shaft rotates. In the present construction the block 49 'may be adjusted to give a reciprocation varying from zero to one quarter of an inch. The pin 52 extends into an opening in the block 53 mounted within a channel 54 formed in a downwardly extending boss 55 on the under side of the slide 4.y

The channel 54 extends in 'a direction transversely of the slideway 2 3. It will therefore be seen that as the shaft 46 rotates and With it the eccentrically located pin 52, the slide 4 will be reciprocated longitudinally of the slideway 2 3 and in-a direction 1ongitudinally of the axes of the grinding wheels 5, but that no transverse movement will be imparted to this slide because the block 53 has free sliding movement in the .transverse channel 54. The gearing 44, 45

is a reducing gearing so that the shaft 46 is v rotated ata comparatively low speed, the reciprocatory movement of the slide 4 being 'also at a relatively low speed.

The frame l is provided with a vertically extending wall 56 and on the opposite side of this wall from the slideway 2 3 the frame is provided with a second slideway 57 in which is mounted for sliding movement a slide 58. This slide is provided on its upper side With inclined Walls 59 adapted to form a sliding connection with a V groove in the under side of another slide 60. It will be noted that the slideways 57 and 59 extend in a direction transverse to the slideway 2 3. The slidev'60 is provided with upwardly extending bearing` supports 61 which carry bearing 62, 63 for a shaft 64 mounted to rotate therein the axis o f the shaft extending substantially parallel to the axes of grinding Wheels 5. The shaft 64 carries opposite each grinding wheel a governing wheel 65 which `is rotated at a relativel low speed by means of mechanism which will now be described.

Secured to the wall 56 are bearing brackets 66 supporting a short shaft 67 carrying pulleys 68 and 69. The pulley 68 carries a belt 70 which belt also passes over a pulley on the main-shaft 11. A second belt 71 connects the pulley 69 with a pulley 72 on a. short shaft 73 mounted in bearings 74 carried by the slide 60. An idler pulley 69 mounted on a frame 692 fulcrumed on sha-ft 67, is pressed against belt'71 by a spring 693, secured at opposite ends to the' lframes 692 and l, and keeps the belt tight in a well known manner. On the opposite side4 ofthe bearing 74 the shaft 73 is provided with a bevel gear 75 meshing with a second bevel gear 76 on the shafty 77 extending at right angles to the axis of the shaft 73, l

this shaft being mounted in a frame 78 adjustably secured on the slide 60. This latter shaft 77 is provided with a worm 79 meshing with a worm-wheel 8O upon the shaft 64 carrying the work-governing wheels 65. This train of driving mechanism from the shaft 11 rotates the governing Wheels 65 in a direction counterclockwise as viewed in Figs. 2 and 3 at a relatively low .rate of speed. Y l

Mounted upon an upstanding portion 81 of the frame 1 by means of suitable supportg ing means is a work-rest or support A82, there being one of these supports between each pair of grinding and governing wheels..v

The supporting means for this work-support comprises a bracket 82 mounted upon a block 83 secured to the upstanding portion 81, the bracket 82 being secured upon the block 83 by means of bolts 84, the heads of which extend into -slots 83 formed upon the upper end of the block 83, the other end of the bolt )passing through an outstanding lug 85 upon the bracket 82 (Figs. 6 and 7). Above and spaced from the lugs 85 the bracket 82 is provided with other outstanding portions 86 each provided with a vertical hole through which 'extends the vertical leg 87 of an L-shaped bolt, the horizontal leg 88 ofthis bolt being adapted to enter a hole or socket drilled in the end of the work-rest 82, as shown in Figs. 6 and 7 the lower end of the vertical leg 87 of the L-shaped bolt being provided with a nut 88 .by means of which the work-rest 82 may be clamped in the V-shaped groove 89 formed in the top surface of the bracket 82. In operation'the work represented in dotted lines at 90 in Figs. 6 and 7 rests upon the top of this tubular support 82 and is adapted to freely rotate thereon during the grinding operation.

As during` the grinding operation the work 90 is not fed across the surface of the grinding wheel it is necessary in bringing the work to grinding position and discharging it therefrom that one of the wheels be moved away from the other, Either wheel may be moved to allow for the insertion and removal of the work, but practically it is easier and more convenient to move the governing wheels 65 with respect to the grinding wheels 5. This movement is imparted to the governing wheels through the slide 60 upon which said wheels are mounted. It is most convenient to drop the work to the workrest from above and to remove the work from the machine by allowing it to drop off the work-rest at the completion of the grinding operation into a chute below the governing Wheels 65. It is therefore necessary that after the grinding operation is completed, the grinding wheels with the work-rests, and

-the governing wheel or wheels be separated a sufficient distance to allow the work to drop from the rest between it and the surfaces of the overning wheels into the trough 91. It 1s preferable to obtain this separation by retracting the governing wheel or wheels away from the work-rest. After the finished work has dropped into the trough the wheels 65 must be advanced toward the work-support a sufficient distance to prevent the unfinished work passing between it and the work-rest when this piece of unfinished work is dropped on to the rest. The governing wheels\65 are then advanced to press the work against the grinding wheels and are givena slow feeding movement during the grinding operation. These retracting and advancing movements are imparted to the slide carrying the governing wheels through two/cam elements 92 and 93 operating in series.

Secured At-o and extending downwardly from the bottom wall of the slide 58 is a block 94 provided with a downwardly eX- .,tending lug 95 and an'anti-friction roller cam element 93 is also provided with lugs and 101 in which is adjustably supported the ends of an adjustable cam element 102 as more clearly shown in Fig. 5. The lug 98 is provided with two straight surfaces 103 and 104. between which is an inclined surface 105 and opposed to these surfaces the lug 99 is provide with an inclined surface 106 substantially parallel to the surface 105 and straight surfaces 107 and 108 parallel` to the surface 104 but between the two with a substantially V-shaped projection 109. The cam element 102 is 1ocated on the opposite side of the lug 109 and is provided with a straight but in clined cam surface 110 which coacts with the lug 95. The cam element 102 is provided on each end with a threaded stud 11.1 and 112 having nuts by which the cam element may be adj/usted longitudinally to vary the effect of the cam surface 110 upon the lug 95. The cam element or plate 93 is slidably mounted in a guideway 113 in the frame 1 and is guided therein by means of guide-plates 114. The cam-plate 93 is provided on its under surface with lan antifriction roller 115 mounted on a stud 116 secured in the plate, the stud and the roller projecting downwardly through a convenientslot 117 formed in the frame y The antiesv friction roller 115 tracts with a cam-groove 118 in the cylindrical surface of the cam4 element 92. This groove is shaped to re- 1 ciprocate the plate 93 in a direction longitudinally of the axis of the grinding and governing wheels. By varying the shape of this slot 118 the movements of the plate 93 of course may be varied as desired to ad- Vance and retract the governing wheels\65 in different timing relations. 1n the present embodiment this groove is Ishaped substantially as shown in Fig. 9 in which passage of roller 96 through the inclined portion t` moves plate 93 while the wheels 65 are being retracted from the guiding wheel to allow discharge of the work, portionb brings the wheels through their first ad.

vancing movement to loading position, c is the loading position and d is Vfor the grinding operation. The cam element 92 is mounted on a shaft.119 provided with a worm-wheel 120 which meshes with a worm 121 mounted on the shaft 122 extending at right angles to the shaft 11 in the lower part of the frame 1. A second shaftA 123 parallel with the shaft 122 is provided and it has a bevel gear 124 meshing with a bevel gear 125 on the main-shaft 11. The other end of the shaft 123 is provided witha spurgear 126 meshing with the second spur-gear 127 on the shaft 122. Between the spurgear 12T and the worm 121 is provided a clutch 128 of any usual construction with a lever 129 extending beyond the frame 1 so tliat driving connection between the spurgear 127 and the worm 121 may be disconnectedat any time to stop the automatic advancing and retracting of the regulating wheels 65.

As it is desirable that the regulating wheels be given a rapid retracting movement from the work-rest after the grinding operation is completed to allow the work to drop from the rest into the trough 91, this movement is imparted tothe supporting slide 58 by the inclined surface 105 reacting against the anti-friction roller 96 as the cam-p'ate 93 is moved to the right as shown in Fig. 5, the anti-friction roller 96 being then in the dotted line position shown in this figure. The governing wheels 65 are advanced to the grinding position in two stages both-.ot

l which are comparatively rapid movements.L

The first stage is caused by the action of inclined surface 106 on the anti-friction roller 96 as it is moved to the left as shown in Fig. 5. This advances the governing whees 65 sufficiently close to the work-rest to prevent work dropping from the rest into the chute 91, but it is not suiciently advanced to press the work against the grinding wheel,

.The governing wheels are retained in this position while the roller 96 advances along the dwell 107 and during this dwell a piece of unfinished work is dropped on to the work-rest by automatic means which will later be described. After this piece of work has been dropped onto the rest the incline 109' on the projection 109 advances the governing wheel to ,grinding position to press the piece of work against the surface of the grinding whe-el 5. During thegrinding operation, however, there must be a very gradual feeding movement imparted to the governing wheels 65 and this is attained by the action of the slightly in'cli'ned cam-Surv .face 110`against the projecting lug 95. Atter the'lug 95 has passed throughout the entire length of the inclined camesurface 110 the grinding operation is continued for a' short time until equilibrium is obtained, that is, until the work has been sufficiently reduced that there is practically no pressing ofthe work by the wheel 65 against the grinding wheel. -This action is allowed by means of la dwell which may be an extension of the surface .110 or may be in the camgroove 118.

As pointed out above the yslide 60 sup portingthe governing wheelor wheels 65 is slidably mounted upon the slide 58, but this mounting is wholly for4 the purpose of adjustment. The slide 58 is provided with an upstanding lug 130 having threaded en.. gagement with which is a screw 131 mounted in a bearing 132 on the slide 60. The outer end of this screw 131 is provided with a worm-wheel-.133 meshing with a worm 134 secured on a short shaft 135 rotatably .mounted ina bearing 136, the other end of this shaft being provided with agraduated disk 137 having handle 138 by means of which it may berotated to rotate the screw 131 to give tine adjustments to the governing wheels 65. The bearing -136 is pivotally mounted on the slide 60 in the same manner as is the bearing 36 mounted on its support 37, that is, so that by loosening a nut 139 on a bolt extending througha curved slot in this bearing theworm 134 may be swung out of mesh with the wormwheel 133, and as the shaft 132 is square at 140 a crank may be placed thereon to obtain a rapid adjustment.

The work is automatically fed to the work-rest from a magazine or hopper 141 placed above the grinding point as shown in Fig. 2. This magazine or hopper may be of any desired construction and is adapted'to hold a plurality of unfinished pieces of work 148. In the present instance the lower part of the magazine has a short vertical guide passage 142 which is adapted to contain one or more pieces of work and through the lower end of which a plunger rod 143 passes. a supportingsurface having a bulge 144 between the lower end of the chute 142 and Aa second chute 145 for guiding the work Below the plunger-rod is tached in any suitable' manner, in the present instance, by a set-screw 146 to an upstanding support 147 mounted on and movable with the support for the governing wheels 65. In the present instance as there are two sets of grinding wheels there are two plungers 143, one adjacent each wheel and con tact with the two opposite ends of a piece of the work 148 so as to give a more reliable operation. It will be obvious that when the governing wheels 65 are retracted under the action of the'cam 105 to allow the work work from passing a It is not necessary 5 short time.

dropped the cam 109 advances the governto drop from the work-rest the plunger 143 will also be retracted and allow the piece of'vwork to drop into the recess 149 at its lower end, the bulge 144 preventing this into the chute 145. lli-hen, however, the governing wheels are advanced under the action of the cam 106 the plungers 148 push 'the work over the bulges 144 into the chute 145 `so that the work drops onto the rest. The work drops while the governing wheel 65 is not being advanced or is being advanced at a retarded rate of speed, that is, while the anti-friction roller 96 is'on the dwell 107.

that the advancing movement of the wheels'be stopped while the work is dropped onto the work-rest, but sufficient time should be allowed for the work to reach the rest before the governing wheels are advanced to grinding position. This time allowance may bel obtained either by stopping the advance movement of the governing wheels or by merely retarding it or advancing them at a reduced speed for a After the work has been ing wheel to press the work against the grinding wheel as described above. In order to properly guide the work to the workrest and to prevent its coming in contact with the grinding wheel before it has reached the rest and the governing wheel 65 is advanced to press it against the grinding surface as. desired, the 4inner wall 150 ofthe chute 145 is extended downwardly as shown at151 close to the surface of the Lgrinding wheel and nearly down `to-the work-rest. This arrangement effectively keeps the work from coming in contact with the grinding wheel 5 until-the work has been placed in proper grinding position.

As the grinding wheels in operation necessarily wear and under continued opera- 4tion become more or less untrue they must :be trued up in order to produce accurate work. This ope-ration may be conveniently performed by means of a truing tool mounted upon the top of the guard 152 extending over the grinding wheel. In the present construction, mounted o n a Hat surface of this guard is an upwardly extending bracket 153 provided with a vertical guideway 154 in which is mounted a slide 155. This slide is provided with .a horizontal guideway 156 'in which is mounted a second slide 157, the second slide carrying the tool 158 provided with a diamond point 159. The slide 155 may be in two sections, one of which is pivoted to t-he other by means of a stud 160 and-is provided at its upper end rwith a curved slot 161 through which extends a bolt 169, the center of curvature of the slot being the center of the stud 160. By loosening the nut on the bolt 162 the outer sec- 5' tion of the slide 155 may be given slight angular adjustment to taper the surface of the v grinding wheel or to place the tool so as to make the surface cylindrical as desired during the finishing operation as will be obvious, the tool being moved over or across the surface ofthe wheel by means of a screw 163 provided with a hand-wheel 164 having scre\\'-tlufeaded engagement with the slide 157. The vertical position of the tool may be determined by means of a similar screw 165 having a graduated hand-wheel disk 166 having screw-threaded engagement with the vertically movable slide 155 in a. manner well known.

In dressing or truing the surfaces of the governing wheel 65 each wheel should be speeded 'up and this operation is obtained through a second short shaft and suitable gears mounted inthe bracket 78. A stud 167 is secured in the bracket 78 with its axis parallel with the shaft 77 and mounted upon this stud is a spur-gear 168 adapted to mesh with a spur-gear 169 on the shaft 77. Integral with or secured to the spurgear 168 is a bevel-gear 170 which meshes with a second bevel-gear 171 geared to a short shaft 17 2 'also mount-ed in the bracket 78 and which is provided with a spiral gear 17 3. Mounted upon the supporting shaft 64 for the governing wheel beyond the worm 7.9 and .worm-wheel is a second spiral` gear 174. The bracket 78 is provided with a curved slot 175, and a bolt 176, secured to the frame, extends through this slot and is provided on its end with a nut 177. By loosening the nut 177 the frame 78 may be swung about the shaft 73 as a pivot, removing worm 79 from in mesh with the wormwheel 80 and moving the spiral-gear 17 3 into mesh with the spiral-gear 174. The gears are so proportioned that this arrangement will increase the speed of the governing wheels 65 to give the propersurface speed for the truing operation. After the truing operation is completed the bracket 78 is swung in the opposite direction about the shaft 73, removing the gear 173 from in mesh with the gear 1.74 and restoring the worm 79 into mesh with the gear 80 which is the normal driving relation for the grinding operation.

The truing point is mounted in a holder 1.85 on a slide 186 mounted on a second slide 187 the two slides being mounted ou V guides to slide in directions at right angles to each other, slide 186 being movable toward and from the governing wheel transverse the axis thereof by means of a screw operated by hand-wheel 188, and slide 187 being movable in a direction parallel with the axis of wheel 65 by a screw and hand-wheel 189 to move the tool across the surface of the wheel. In the present instance as there are two governing wheels there are two sets of tool 184 having a diamond` water.

slides 186 and 1.87 with a truing tool 184 for each one, but they yare both moved across the surfaces of the wheel at the same 4time by means of the lscrew operated by hand-wheel 189, as theslides 187 are connected by a link 190.

being ground, means are provided for flushing it and the grinding wheel surface durlng the normal grinding wheelV operation. A receptacle 180 is provided for emery char ed water and a pump driven in any suita le manner from the power-shaft 11 or any other suitable source of power pumps this water through a system of piping 181 to discharge nozzles 182, located adjacent the surface of the grinding wheel 5 above the grinding point so 'that this water is discharged onto the surface of the grinding wheel and the work during normal grinding operation, the water passing downwardly into the chutes and other hollow spaces within the frame and is drained back into the receptacle or tank 180 to be used over again, there being a continuous circulation of this In operation the grinding wheel 5 is rapidly rotated in the direction of the arrow,

Figs.,2 and 3, the surface contacting with the work moving downwardly' toward the top of the work-rest. The governing wheels 65 are slowly rotated in the same direction as also shown by the arrows, the surface con'- tacting with the work moving upwardly away from the top of the work-rest. Itwill be seen that when this wheel presses thework against the surface of the grinding wheel, the work 1s rotated slowly 1n a clockwise direction as vlewed 1n, F1gs..2 and 3,

and the surface thereof is ground by the ac tion ofl the grinding wheel 5. Assuming that the operation of grinding a piece of Work has been completed, under the action of the cam surface `105, the governing wheels 65 preferably are rapidly retracted away from the work-rest a sulicient distance to allow the work to drop from this rest into the chute-91 from which it passes into a suitable receptacle. To obviate all possibilityv of th work remaining on thel rest vwhen the wheels 65fare retracted a spring 183 is se cured upon the support for the work-rest as shown in Fig. 2 and rests against the side of the work adjacent the grinding wheel and normally tends to Apress the work. against the surface of the governing wheels 65. It will therefore be obvious that when the governinfr wheels'65 are retracted', this s 'rino' will force the work to the left as shown in Fig. 2, away from the surface of'the grinding wheel so that it will necessarily fall intoA the chute 91. i The governing wheels 65 are now advanced under theaction of the cam 106 to a position spaced somewhat from the work-rest but not sufficient to allow the work 'to pass between it and the work-rest.

-cated This advance movement ofthe wheels 65 alsoadvances the plungers 143 which transfer a piece of Workl from the bottom of the chute 142 into the chute 145 where it is guided to the top of the work-rest. The governing To vprevent heating of the work as it isv wheels 65 are now advanced under the action of the projection 109 to normal grindthe work to rotate it as will be obvious.

During this grinding operation the wheels -65 are slowly advanced toward the grinding `wheels an amount equal to the'- amount of stock which'is to be removed from the work, after which the grinding operation is continued a shorttime Without any feedingl movement toward thegrinding wheel being imparted to the governing wheels 65. lhe work is now finished and the governing wheels 65- are again retracted to allow removal of the .work from the work-rest. During the grinding operation the slide 4 upon 4which the grinding wheels 5 are mounted is preferably continuously reciproin a direction longitudinally of the axis .of these wheels by means of the gearing 43, 42, 44, 45 and the crank 52 so as to Give a uniform grinding throughout the surface to be ground and to ,compensate for any inequalities in the surface of the. grinding wheel such as occur because of unequal wear due to non-uniform hardness of different portions of the grinding wheel.

In the present construction as will be noted there are two sets of grinding and regulating wheels spaced from each other longitudinally of their axes of rotation. By this arrangement two independent and spaced bearing surfaces may be simultaneously ground upon a single element such as a derstood, however, that this invention 1s not limited to two scts of grinding-wheels as more may be employed and the same prining Wheel to grind one bearing surface at a time such as the Shanks of headed bolts and similar articles.

It will be seen from the foregoing that the machine is entirely automatic, the work being automatically discharged from and fed to the grinding position as the governing wheels 65 are automatically retracted and advanced under the operation of the cams.

Having thus set forth the nature of the invention, what I claim herein is- 1. A centerless grinder comprising low and high speed wheels adapted to simultaneously press in opposite directions upon a work-piece, a work-rest between said wheels permitting the work-piece to rotate and adjust itself to the opposed pressures of said ciple may be employed with a single grindpiece to grindingposition on said work-rest,

and automatic means for relativelyV approaching said'wheels to grindthe workpiece to size and for relatively separating them when the grinding operation is conipleted to allow the work-piece to "fall from its support through the space provided by separation of said wheels. l

2. A C enterless grinder comprising low and hiffh' speed wheels adapted to simultaneousy press in opposite directions upon' a work-piece, a work-rest permitting thev work-pieceto adjust itself to the opposed pressures of said' wheels, 'automatic -means for feeding'a work-piece tol grinding position on the work-rest, and automatic means for relatively approaching said wheels to grind the work-piece to size and for relatively separating them when the grinding oper-ation is completed to allow the Workpiece to. fall from its support, said automatic feeding means being timed to feed a work-piece to grinding position after said wheels have been relatively approached part way from work-discharging position to grinding position.

3. A centerless grinder comprising low and high speed wheels adapted 4to siinultaneously press lin opposite directions upon a, rotatable work-piece, a work-rest permitting the work-piece to rotate and adjust itself to the opposed pressures of said wheels, 'automatic means for imparting a two-stage approachingmovement to -said` wheels to relatively place them first in workrcceiving position and second in grinding positiomsaid meansr being constructed to relatively separate saidwheels when the grinding'operation is completed, and means for feeding-a work-,piece to the'work-rest after the wheels have lbeen relatively approached to work-receiving position.

erning wheel 'having its periphery opposed port between said Wheels permitting the woi'k to adjust itself to the simultaneous opposed pressures of said wheels, means for rotating said wheels at relatively dierent' speeds,fand means for continuously reciprocating said grinding wheel longitudinally of its a'X' during normal operation. l

5. A centerless grinder comprising periphand'g work-governmeans for rotating said wheels, a work-rest betweenthe Aperipheries of the said wheels, automatic means for advancing one of the wheels toward and from the other wheel to press the work against the' grinding wheel and allow removal of the work from grinding position, vand means' for continuously reciprocating the grinding wheel wheels transverse A centerless grinder compnising va .peripheral grinding wheel and a work-gowl longitudinally of its axis duringnormal operation.

6. Acenterless grinder comprising peripherally opposed grinding and work-governing wheels, means for rotating said wheels at relatively different speeds," a support for the work between the wheels, means for adi vancing the governing wheel to bring the work into Contact with the grinding wheelA and to reti-act said governing wheel -to allow discharge of the Work from grinding position, and automatic means for continuously -reciprocating the grinding wheel longitudinally of its' axis during the grinding opeia tion.

7. A centerless. grinder comprising peripherally opposed wheels adapted for simultaneous engagement with the work, means for rotating said wheels, a work-rest between said wheels pei'- mit-ting the work to accommodate itself to the simultaneous opposed pressures of said wheels, a supply magazine or hopper for holding the work to be operated upon, means for causing relative movement between said their axes to allow for insertion and discharge of the work, and means operable' by the relative movement between said wheelsl for transferring a p iece of work from the magazine or hopper tothe grinding position.

press upon a piece of wollt in grinding position therebetween, means for relatively separating said wheels to allow the discharge of the work from grinding position,- and means governed by the relative approaching movement of said wheels to cause a piece of work to be dropped from said magazine or hopper onto said work-rest.

grinding and governing iio 9.' A centerless grinder comprising opposed grinding and governing wheels, a

work-rest between said wheels, a supply magazine or hopper adapted to hold the work to be operated uponv above said workres't, `automatic means for relatively separating the governing wheel and the grinding wheel to allow discharge of lthe finished work from grinding position, automatic means for relatively approaching the gov-- erning wheel and the grinding wheel in two steps the rst step cient to bring the work into contact with the grinding wheel, means governed by the relative approach of said wheels to cause a piece of work to, drop fromv the magazine orhopper to the work-rest at4 the completion of said first step, said 'relative approaching being a movement insuftimeans being adapted to subsequently further relatively move said wheels to bring the work to grinding position.

' 10. A centerless grinder comprising opposed grinding and governing wheels, means for rotating said wheels, a work-rest between the wheels,- means for retracting the governing wheel from and advancing 1t toward the.

grinding wheel to allow for discharge from and placing work on the rest, and yielding means adapted to force the work from the rest asthe governing wheel is retracted..4

12. A centerless grinder comprising opposed s aced grinding and governing wheels, means or rotating said wheels, a work-1 est between the wheels, a work-magazine or hoper spaced above the rest, and spaced guides orming a substantially vertical chute to,

guide the Work from the magazine hopper to the rest, the walls of the chute being arranged -to prevent contact of the work with the grinding wheel as it passes to said rest.

l. 13. A centerless grinder comprising opposed spaced'grinding and governing wheels,

means for rotating said wheels, a work-resti between the wheels, a work-magazine or hop-l per spaced above the rest, and spaced guides forming a chute`to guide the work from the magazine or hopper to the rest, means for retracting and advancing the governing wheel relatively to the grinding wheel to allow for the discharge and feeding of the wiork and to bring the work to grinding position,

and means governed by the advancing movement of said wheel to transfer a piece of work from the magazine or .hopper to said chute.

14. A centerless grinder comprising a piurality of sets of peripherally opposed grinding and governing wheels, the wheels of each set rotating in the same direction at different speeds, the sets being spaced from each other longitudinally of the axes of the wheels so as to siultaneously grind to finl ished size'a plurality of aligned bearings on a single element, means for rotating the l. grinding and governing wheels, means for relatively moving said wheels transversely of their axes, and a. work-rest between the wheels of eachsct.

15. Acenteriesu grinder comprising a plurality of sets of peripherally opposed grinding and governing wheels, the sets being spaced from each other longitudinally of the axes of the wheels'so as to simultaneously vgrind a plurality of aligned bearings on a spaced from each other longitudinally of the' axes of tbe wheels so as to simultaneously grind a plurality -of aligned bearings on a single element, means for simultaneously retracting and` advancing said governing l wheels relatively to the grinding wheels to allow for removal and insertion of the work and bring the work to grinding position,

a work-magazine -above the work-rests, a

work-guiding chute from the magazine to each work-rest, and means operated by the advancing movement of the governing wheel .tol transfer work from the magazine to said chutes.

17. A l.centerless grinder comprising a frame, a'movable slide mounted in said frame, bearings on said slide, a peripheral grinding wheel mounted to rotate in said bearings, .a main power-shaft, operative means connecting said shaft and slide whereby the slide and grinding wheel are continuously reciprocated longitudinally of the axis of the wheel during normal operation, a second slide mounted on said frame and adapted to be shifted in a direction transverse the axis of the grinding wheel, a governing wheel mounted on said second slide,

means for rotating said wheel, a work-rest between the two wheels, and means connecting said second slide and said main-shaft, to

retract and advance said governing wheel.

with respect to the grinding wheel in certain timing relation to the grindingoperation 18. A centerless grinder comprising a frameLa pair of slides mounted on said frame andadapt-ed to be shifted in directions substantially at right angles to each other, a grinding wheel mounted on one of said slides, a governing wheel mounted on the other slide with its periphery opposed to that of the grinding wheel, means for rotating said wheels, a power-shaft, and operativeconnections between the slides and the shaft whereby the slidesl are automatically-shifted.

'19.' A centerless grinder, comprising a frame providedwith a plurality of slideways, slides vmounted on said slideways, op-

posed lgrinding and governing wheels mounted on said slides so that they may be moved toward and from each other, a work-rest between said wheels permitting the work to adjust itself to the simultaneous opposed pressures of said wheels, a main power-shaft mounted in bearings in said frame below said Wheels, and means for driving said wheels from said shaft.

20. A centerless grinder comprising a frame, a grinding wheel mounted on said frame, means for rotating said wheel, a slide movably mounted on said frame, a governing wheel mounted on said slide, means for rotating said governing wheel, a work-support between said wheels permitting the work to adjust itself to the simultaneous opposed pressures of said wheels, means for moving the said slide with the governing Wheel toward and from the grinding wheel in certain timing relation with the grinding operation, said means comprising a movable cam-plate having cam-surfaces, means on the slide cooperating with said cam-surfaces, a cam-disc provided with a cam-groove, means on the cam-plate coacting with said groove, and means for rotating the cam-disc.

21. A centerless grinder comprising opposed grinding and governing wheels, a

work-support between said wheels, and automatic means for retracting and advancing said governing wheel relatively to the grinding wheel to allow for discharge and insertion of work between said wheels, said means comprising two cam means operating in series, and means for operating said cam means.

22. A centerless grindercomprising opposed grinding and governing wheels, means for supporting one of the wheels so that it may be moved toward and from the other wheel, a work-rest between the Wheels adapted to support the work during the grinding operation, and automatic means for advancing the movable wheel .to press the work against the other wheel and for retracting said wheel to allow of the discharge of the work after the grinding operation is oompleted'.

23. A centerless grinder comprising low and high speed wheels adapted to simultaneously press in opposite directions upon a work-piece, a work-support between said wheels permitting the work-piece to adjust itself to the opposed pressures of said wheels, and automatic means for relatively 'approaching said wheels to grind the workpiece to' size and for relatively separating them sufficiently to permit the work-piece' to fall b gravity from said work-support throug the space between the latter and one of the wheels.

In testimony whereof, I have signed my name to this specification.

WILBUR J. Paars. 

